JPH0563402B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATIONS The present invention relates to soda ash and hydrogen peroxide solid compositions that have good storage stability and are useful for providing alkali peroxide when dissolved in water. <Prior Art and Problems to be Solved by the Invention> Sodium carbonate, also known as soda ash, is a solid addition compound with at least two hydrogen peroxides, 2Na ₂ CO ₃ 3H ₂ O ₂ (sodium carbonate It is known to form 2Na ₂ CO ₃ .3H ₂ O ₂ .2H ₂ O (sodium carbonate sesquiperoxide hydrate). Sodium carbonate peroxide is commonly known as sodium percarbonate, and is also referred to as sodium carbonate peroxide or sodium carbonate perhydrate, and is abbreviated herein as "SCP." SCP has been the subject of much research because it has many effective uses as a source of peroxygen when dissolved in aqueous solutions. Despite the high active oxygen content (more than 15%), great solubility in water, relatively cheap raw materials and very low negative environmental impact, SCP has not yet reached the commercial popularity of sodium perborate. This is because SCP exhibits the disadvantage of being much more unstable than perborates. Under the same conditions, solid SCP undergoes decomposition and loses substantially more active oxygen than perborate decomposition. This problem is particularly undesirable in cartons of retail detergent solids, during the detergent production process, or during storage after delivery to the detergent manufacturer. Removal of impurities such as heavy metals that promote decomposition reactions reduces the instability of SCP aqueous solutions. Many solutions have been proposed to alleviate this stability challenge of solid-state SCPs, but to date no complete success has been achieved. US Pat. No. 2,380,620 discloses that sodium silicate, magnesium sulfate or gum arabic are unsatisfactory stabilizers when included in the reaction mixture. This patent teaches that addition of diphenylguanidine, preferably in the presence of conventional stabilizers, reduces decomposition. US Pat. No. 2,541,733 teaches a method for incorporating magnesium carbonate and silicate into SCP crystals during the formation of SCP crystals from a mother liquor. US Patent No.
No. 3,677,697 teaches the addition of silicate and benzoic acid into the crystals before drying. US Pat. No. 3,951,838 discloses that attempts at chemical stabilization, primarily with magnesium silicate, are generally ineffective for long-term stabilization of SCPs, especially in humid atmospheres. Instead, this patent teaches coating and drying the particles with aqueous silica gel. U.S. Pat. No. 3,977,988 to Fumikatsu et al. discloses that SCP coating with paraffin, polyethine reglycol or sodium pyrophosphate is impractical and describes coating of particles with silicates and fluorosilicate films. Suggests. No. 3,979,318 by the same inventor teaches coating SCP particles with hydrophobic liquids. U.S. Pat. No. 4,075,116 discloses other salts known to form perhydrates such as sodium sulfate, sodium pyrophosphate, sodium glycoheptanoate,
He teaches co-crystallization of SCP with sodium perborate, etc. Prior to SCP crystallization, U.S. Patent No. 4,409,197
The incorporation of N,N,N',N'-tetra(phosphonomethyl)diaminoalkane into the reaction solution is taught. US Pat. No. 4,171,280 and US Pat. No. 4,260,508 only partially convert sodium carbonate or sodium carbonate monohydrate into SCP by dispersing sufficient hydrogen peroxide onto sodium carbonate particles, and the activity as SCP is less than 6%. It is taught that non-caking bleaching compositions containing oxygen can be formed. US Patent No. 4260508
No. 2, No. 1, No. 1, No. 1, No. 1, No. 1, No. 1, 2003, teaches the addition of sodium phosphate to the composition as a stabilizer. Both patents are against the production of products containing more than 6% active oxygen, stating that less than 6% active oxygen (40
% SCP) is required. Low content is also critical for caking and preventing demixing or separation of the formulation. However, such low content values are of great value to detergent formulations due to increased transportation costs, the cost of added inert raw materials, and the capital costs due to the large equipment needed to obtain the desired output. It will be disadvantageous. An even greater obstacle is prescription preparation at 6%.
The end use for making compositions containing active oxygen is limited by low analytical values. SUMMARY OF THE INVENTION The present invention provides a stabilized soda ash peroxygen carrier composition comprising sodium carbonate, sodium carbonate perhydrate, and a stabilizing amount of sodium carbonate for use in the composition. a "stabilizer" characterized in that it consists of a "particulate solid" in which sodium carbonate is present in the composition at least 1 mole for each mole of "available water" in the composition; The disadvantages of the prior art have been overcome by providing a peroxygenated soda ash carrier composition. Particularly preferred embodiments of the invention include sodium carbonate, SCP and 0.1% to about 3% by weight.
% formula: [However, Y is hydrogen or hydroxyl, and R is hydrogen or an aliphatic hydrocarbon group having 1 to 6 carbons.] A particulate solid having enough sodium carbonate present in the composition to provide from 1 to 5 moles of sodium carbonate for each mole of water. Those skilled in the art will recognize that the effective amount of stabilizer will depend on the stabilizer chosen. It is critical that sufficient sodium carbonate be present in the composition so that it can combine with all of the available water in the composition to form sodium carbonate monohydrate; the term "available water" includes water that is chemically available as hydrogen peroxide, water of crystallization of sodium carbonate hydrate, and free water temporarily present in the composition. As used herein, the term "particulate solid" refers to particles, ideally all of which contain sodium carbonate, SCP, and stabilizer, and refers to a physical mixture in which the sodium carbonate and SCP are separate particles. shall not be included. However, such an ideal is not practical, especially in compositions containing 5 moles of sodium carbonate per mole of available water. Preferably, the main part (most part) of the particles is sodium carbonate, SCP
and a stabilizer, preferably 90% of the particles consist of sodium carbonate, SCP and stabilizer. Such compositions, in contrast to the teachings of U.S. Pat. No. 4,171,280, combine particles of anhydrous sodium carbonate with a limited amount of a solution of hydrogen peroxide containing stabilizers and having a concentration greater than 70%. contact with the amount
It can be prepared by forming a mixture of SCP, sodium carbonate monohydrate, and some unreacted anhydrous sodium carbonate. For example, particles of anhydrous sodium carbonate can be contacted with a substantially anhydrous (100%) hydrogen peroxide solution of diphosphonic acid. More simply, the method of co-pending US patent application Ser. No. 254,063 can be used. Preferably, the analysis (content) of the composition is between 45% and 75% by weight as SCP (1.46% as hydrogen peroxide).
% to 24% or 7% to 10.6% as active oxygen)
It is. Preferably, the analytical value (content) of the composition is
65% to 75% as SCP (21% to 75% as H ₂ O ₂
24% or 9% to 10.6% as active oxygen). Unless otherwise specified, all percentages used herein are rounded numbers or significant figures. Additionally, these compositions are useful as a solid and storage stable source of peroxygen when incorporated into detergent compositions. Compositions containing 45% to 75% as SCP have been found to be particularly useful compounds in detergent formulations. Unexpectedly, the composition was stable without the coating required in the prior art. Furthermore, even when the composition content is between 45% and 75% SCP and the water vapor pressure is substantially greater than the equilibrium vapor pressure of sodium carbonate monohydrate, storage in a humid atmosphere may It has been found that things do not cake. The inclusion of "stabilizers" in the composition is critical to the present invention. It has been found that the stabilizer not only prevents the composition from decomposing, but also that the stabilizer changes the physical properties of the composition as indicated by the equilibrium vapor pressure of sodium carbonate monohydrate as well as the active oxygen stability during storage. . Sodium carbonate monohydrate and anhydrous sodium carbonate as revealed by the standard analytical methods used appear to be clearly oversimplified. A novel composition for the purposes of the present invention is presented as if it consisted of a simple mixture of SCP, anhydrous sodium carbonate, sodium carbonate monohydrate, sodium carbonate decahydrate and a stabilizer. In order to clarify the new composition “soda ash peroxygen carrier (Soda
Particularly preferred diphosphonic acids are the commercially available 1-hydroxyalkyl-1,1-diphosphonic acids; 1-Hydroxyethylidene-1,1-diphosphonic acid sold under the Dequest2010 brand.Surprisingly, published data show that diphosphonic acid or salts change the equilibrium vapor pressure of sodium carbonate monohydrate crystals. was found to allow its dehydration under extremely mild conditions compared to that of anhydrous sodium carbonate, which is quite unexpected in view of the fact that diphosphonic acid is hygroscopic. Excess in SAPC can be removed by forming sodium carbonate monohydrate, even the water present as sodium carbonate decahydrate. Standard analytical methods that can be used to analyze soda ash carrier compositions are: Sodium carbonate or total alkalinity (TA) is determined by titration standardized to the methyl orange end point and expressed as %
Report as Na ₂ CO ₃ (sodium carbonate). Active oxygen (AO) can be measured by titration using a standardized permanganate or ceric sulfate solution, or by iodometric titration, in which liberated iodine is titrated using a standardized thiosulfate solution. hand,%
AO, % _H2O2 (2.125 _x %AO) or %SCP (6.542
×%AO). For detailed methods, see FMC Corporation's Technical Bulletin 59.
“The Analysis of Hydrogen Peroxide Solutions”
Water (% H ₂ O) is conveniently measured by thermogravimetric analysis or by weight loss when left in a desiccator at room temperature. Available water (% AW ) is approximately
It is heated to 200° C. and determined gravimetrically by measuring the weight gain of a suitable adsorbent, such as magnesium perchlorate, in the gas stream. Available water is %AW=% _H2O +0.529×%
Estimated to be H ₂ O ₂ . The following examples are presented to explain to those skilled in the art how best to practice the invention, and are not intended to limit the invention. Stabilizers are exemplified using preferred commercially available diphosphonic acid compounds. Laboratory samples for SAPC are made by adding the desired amount of diphosphonic acid (when needed) to 70% by weight hydrogen peroxide.
A mixed solution was formed and prepared. Anhydrous sodium carbonate was introduced into a laboratory rotary evaporator equipped with a water bath for temperature control unless otherwise noted. The desired amount of a mixed solution of hydrogen peroxide and 1-hydroxyethylidene-1,1-diphosphonic acid is mixed to ensure homogeneity and either under vacuum or by blowing air over the surface of the reaction mixture. A reaction mixture was formed by sprinkling on soda ash while simultaneously removing water vapor. After spraying the desired amount of the mixed solution, the reaction mixture was taken out as a product. Wet chamber stability was measured by placing crystallization dish samples in a humid chamber at 40° C. and 80% relative humidity. The % hydrogen excess was determined by iodometric titration and measured over 10 days. No correction was made for the amount of water adsorbed to or lost from the sample. Stability was also confirmed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Example 1 With and without diphosphonic acid
SAPC compositions were prepared and their stability was determined in a wet chamber. Soda ash mixtures with hydrogen peroxide alone were unstable at almost all composition levels, the higher the % hydrogen peroxide, the more unstable. Addition of diphosphonic acid along with hydrogen peroxide resulted in stable perhydration. Table 1 is 55%
It is shown that stable compositions containing 75% SCP were made in this manner. Compositions containing more than 75% SCP (more than 25% H ₂ O ₂ ) were unstable despite the presence of diphosphonic acid. Example 2 The stability of compositions containing 55% SCP (18% hydrogen peroxide) is summarized in Table 2. The stability of the 18% hydrogen peroxide mixture on storage at 50° C. and 40% relative humidity is shown in Table 3. These data indicate that a product is produced that is stable to storage at relatively high temperatures and humidity. In addition, compositions made in this manner are compatible with other peroxygen compounds used in the industry, such as sodium monoperborate tetrahydrate and sodium perborate monohydrate and commercially available SCP coated with silicate.
It shows that it is stable as well (Table 4). Example 3 The thermal stability of a composition containing 55% SCP (18% hydrogen peroxide) was determined by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). These analyzes indicate that the composition is approximately
This shows that it is stable up to 150℃. TGA analysis also shows that two waters of crystallization are initially present in these compositions, ostensibly sodium carbonate decahydrate and sodium carbonate monohydrate (Figure 1). The former can be easily removed or converted to the monohydrate. (Table 5) Monohydrate water is quite difficult to remove. The presence of the monohydrate does not result in the severe caking that occurs when the decahydrate is present. Diphosphonic acids surprisingly modify the monohydrate crystals so that the water of crystallization can be removed to form an almost anhydrous product. This is shown in the TGA and DSC analyzes in Figures 2 and 3. This product is not prone to caking upon contact with moderately humid environments. Table 5 and Figure 1 also show that sodium carbonate monohydrate
Published data of 6.06kPa (45.4mm) for water vapor pressure at 40.4℃ and 6.06kPa at 40.5℃ and 80% relative humidity
When compared to the water vapor pressure of (45.4 mm), this shows the unexpected properties of SAPC. According to published data, the sodium carbonate monohydrate formed in SAPC should never absorb moisture from the atmosphere. Example 4 Diphosphonic acid is required for solution stabilization and SAPC stabilization and to facilitate removal of water of hydration. 0.2 in a laboratory Hobart blender
Samples containing %, 0.7% and 1.3% diphosphonic acid were prepared. Table 6 summarizes the effect of diphosphonic acid additives on the stability of the compositions. The amount of additive required is much greater than that required to simply stabilize hydrogen peroxide by chelating with heavy metals.
The SAPC composition was found to be as stable as commercially available (coated) SCP; sodium perborate monohydrate and sodium perborate tetrahydrate. This is shown in Table 4. Example 5 In addition to determining the stability of soda ash/hydrogen peroxide compositions as a function of hydrogen peroxide and moisture, hydrogen peroxide uptake was measured as a function of soda ash particle size distribution. This is shown in Table 7 for a given hydrogen peroxide content. The hydrogen peroxide content of the smaller particles was greater than that of the larger particles. The presence of particulates containing unevenly high concentrations of hydrogen peroxide results in product instability. Example 6 A ribbon blender with water jacket was used as a reaction vessel having a volume of 0.15 m ³ (5 ft ³ ) for pilot scale testing. An aqueous hydrogen peroxide solution, usually containing diphosphonic acid, was pumped from the drum to sparge knolls on each end of the blender. In all cases _a 70% _H2O2 solution was used. Temperature was measured at three points in the reaction mixture using thermocouples and controlled by varying the peroxide feed rate. Cooling was accomplished either by water in the blender jacket or by airflow on or through the bed. The solids leaving the blender entrained in the air stream were captured with a ventilate scrubber and the resulting solution was analyzed for mass balance purposes. Heat balance was carefully controlled using the same method for all experiments. - start the blender, - feed in the weighed amount of soda ash, - start the cooling water, - feed in the H ₂ O ₂ solution until the desired weight has been added, - cool the product and after about 1 hour. Released from the bottom valve. Stability of the product in a room at 50°C/20% relative humidity
A 0.14 m ³ fiber drum was stored and the active oxygen reduction was measured after 19 days. The product was exposed in the drum and topped with a loose lid without a clamp. A summary of the results is shown in Table 8. In all cases,
Peroxide efficiency after addition was 95+%. It is clear that for a stable product a ratio of 1 mole or more of sodium carbonate per mole of available water is critical.

[Table] Table 2 Soda ash peroxygen carrier wet test 40℃, 80% relative humidity, initial H ₂ O ₂ concentration 18% Time (days) Residual hydrogen peroxide % 1 100.0 2 100.0 3 100.0 5 99.5 8 98.6 10 98.6 Table 3 Soda ash peroxygen carrier storage stability 50°C, 40% relative humidity Time (days) Residual hydrogen peroxide % 11 98.4 18 99.8 25 97.1 32 99.8 Table 4 Comparative stability of SAPC with sodium perborate
40°C, 80% relative humidity Compound Residual Hydrogen Peroxide % SAPC 96.5 SAPC (without dibosphonic acid) 16.5 Sodium perborate monohydrate 97.6 Sodium perborate tetrahydrate 96.1 (Coated) Commercially available sodium carbonate peroxide 97.0

[Table] Table 6 SAPC stability with diphosphonic acid concentration 40℃, 80% relative humidity 10 days, 18% hydrogen peroxide % Diphosphonic acid residual hydrogen peroxide% 0.2 81.2 0.7 92.5 1.3 95.9

【table】

[Table] *…The drum is caking solid.

[Brief explanation of the drawing]

Figure 1 shows the results of thermogravimetric analysis of a composition containing 55% SCP (SACP). FIG. 2 shows the results of differential thermal analysis of anhydrous SAPC, and FIG. 3 similarly shows the results of thermogravimetric analysis of anhydrous SAPC.

Claims (1)

Claims: 1. A stabilized soda ash peroxygen carrier composition comprising sodium carbonate, sodium carbonate perhydrate, and a stabilizer for the composition, and wherein the composition comprises sodium carbonate, sodium carbonate perhydrate, and a stabilizer for the composition; A stabilized soda ash peroxygen carrier composition characterized in that it consists of at least 1 mole of particulate solids present in the composition for each mole of available water therein. 2. A major portion of the particles constituting the particulate solid contains amounts of each of the sodium carbonate, sodium carbonate perhydrate, and stabilizer that are effective in combination to reduce the rate of decomposition of the particles. The composition according to claim 1. 3. The composition of claim 2, wherein said major portion is greater than at least 90% of the particles. 4 The stabilizer has the formula: [Provided that Y is hydrogen or hydroxyl, and R is hydrogen or an aliphatic hydrocarbon group having 1 to 6 carbons] or a salt thereof, according to claim 1, 2 or 3, which is a diphosphonic acid or a salt thereof. Composition of. 5. The composition of claim 4, wherein Y is hydroxyl and R is methyl. 6. A composition according to claim 1, 2 or 3, wherein the sodium carbonate is present in 1 to 5 moles per mole of available water present in the composition. 7. A composition according to claim 1, 2 or 3, wherein the composition contains 45% to 75% sodium carbonate perhydrate. 8. A stabilized soda ash peroxygen carrier composition comprising sodium carbonate, sodium carbonate perhydrate, and from 0.1% to about 3% by weight: [However, Y is hydrogen or hydroxyl, and R is hydrogen or an aliphatic hydrocarbon group having 1 to 6 carbons.] A stabilized soda ash peroxygen carrier composition comprising particulate solids present in the composition in an amount sufficient to provide from 1 to 5 moles of sodium carbonate for each mole of available water. 9. The composition of claim 8, wherein Y is hydroxyl and R is methyl. 10. A stabilized soda ash peroxygen carrier composition comprising sodium carbonate, sodium carbonate perhydrate, and from 0.1% to about 3% by weight of 1-hydroxyethylidene-1,1-diphosphonic acid. stabilized solids, characterized in that the sodium carbonate consists of particulate solids present in the composition in an amount to provide from 1 to 5 moles of sodium carbonate for each mole of available water in the composition. Soda ash peroxygen carrier composition.